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Licensed Unlicensed Requires Authentication Published by De Gruyter March 7, 2014

Modeling, Simulation, and Configuration Improvement of Horizontal Ammonia Synthesis Reactor

  • Foad Farivar and Habib Ale Ebrahim EMAIL logo


In this work, one-dimensional heterogeneous model has been developed for an intercooled horizontal ammonia synthesis reactor (HASR) of the Khorasan petrochemical plant. The model is further extended to simulate the HASR with two quench flows. The mass balance, energy balance, and pressure drop equations have been solved simultaneously by fourth-order Runge–Kutta method using MATLAB software to obtain concentration, temperature, and pressure profiles along the reactor beds. For effectiveness factor calculation, a modified shooting method has been used to solve two point boundary value differential equations. The simulation results are compared with the plant data, and good agreement is achieved. In the following, a new configuration for HASR is proposed. The proposed design combines intercooled and two quench flow HASRs. Hence, comparing to the conventional HASR with two quench flows and intercooled HASR, it has higher nitrogen conversion and consequently higher ammonia production rate. The simulation results are compared with the conventional HASRs in order to demonstrate the improved performance of the proposed reactor.


The authors thank the cooperation of Khorasan Petrochemical Company for providing the ammonia plant data.




Activity of hydrogen, ammonia, and nitrogen,respectively



Cross-sectional area of beds



Total concentration


[kcal/kg K]

Specific heat of gas mixture



Effective diffusion coefficient of component i



diffusion coefficient of component i



Initial molar flow rate of nitrogen



Equilibrium constant of reaction



Reverse reaction rate constant



Bed length



Mass flow rate



Average molecular weight


[kmol/m2 h]

Molar flux of component i at catalyst particle






Radial coordinate of catalyst particle


[kJ/kmol K]

Universal gas constant



Equivalent radius of thecatalyst particle


[kmol/m3 h]

Intrinsic rate of reaction









Conversion of nitrogen



Mole fraction of component i

Greek symbols


Porosity of catalyst bed



Effectiveness factor



Heat of reaction


[Pa s]

Fluid viscosity






Intraparticle porosity


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Published Online: 2014-3-7
Published in Print: 2014-6-1

©2014 by Walter de Gruyter Berlin / Boston

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